pgstat: add pg_stat_have_stats() test helper.

Will be used by tests committed subsequently.

Bumps catversion (this time for real, the one in 0f96965c658 got lost when
rebasing over 5c279a6d350).

Author: Melanie Plageman <melanieplageman@gmail.com>
Discussion: https://postgr.es/m/CAAKRu_aNxL1WegCa45r=VAViCLnpOU7uNC7bTtGw+=QAPyYivw@mail.gmail.com

2 files changed, 28 insertions, 0 deletions

diff --git a/src/backend/utils/activity/pgstat.c b/src/backend/utils/activity/pgstat.c
index 111869b2115..7df3fda6484 100644
--- a/src/backend/utils/activity/pgstat.c
+++ b/src/backend/utils/activity/pgstat.c
@@ -872,6 +872,16 @@ pgstat_get_stat_snapshot_timestamp(bool *have_snapshot)
 	return 0;
 }
 
+bool
+pgstat_have_entry(PgStat_Kind kind, Oid dboid, Oid objoid)
+{
+	/* fixed-numbered stats always exist */
+	if (pgstat_get_kind_info(kind)->fixed_amount)
+		return true;
+
+	return pgstat_get_entry_ref(kind, dboid, objoid, false, NULL) != NULL;
+}
+
 /*
  * Ensure snapshot for fixed-numbered 'kind' exists.
  *
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 5f1815727de..2bf8ab8f986 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -2394,3 +2394,21 @@ pg_stat_get_subscription_stats(PG_FUNCTION_ARGS)
 	/* Returns the record as Datum */
 	PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
 }
+
+/*
+ * Checks for presence of stats for object with provided kind, database oid,
+ * object oid.
+ *
+ * This is useful for tests, but not really anything else. Therefore not
+ * documented.
+ */
+Datum
+pg_stat_have_stats(PG_FUNCTION_ARGS)
+{
+	char	   *stats_type = text_to_cstring(PG_GETARG_TEXT_P(0));
+	Oid			dboid = PG_GETARG_OID(1);
+	Oid			objoid = PG_GETARG_OID(2);
+	PgStat_Kind	kind = pgstat_get_kind_from_str(stats_type);
+
+	PG_RETURN_BOOL(pgstat_have_entry(kind, dboid, objoid));
+}